Memory array and method of forming the same

ABSTRACT

A memory array includes a first column of memory cells, a second column of memory cells and a set of switching elements. The first column of memory cells includes a first bit line, a first word line and a second bit line. The second column of memory cells includes the second bit line, a second word line and a third bit line. The first and second column of memory cells are configured to share the second bit line. The first and second bit lines are in a first plane. At least a portion of the first word line and at least a portion of the second word line are in a second plane intersecting the first plane. An amount of bit line switching elements in the set of bit line switching elements is equal to N*2, where N is an amount of columns of memory cells in the memory array.

PRIORITY CLAIM

The present application is a divisional of U.S. application Ser. No.14/060,742, filed Oct. 23, 2013, which is incorporated herein byreference in its entirety.

BACKGROUND

Device manufacturers are continually challenged to reduce the size ofvarious integrated circuits and semiconductor devices while increasingprocessing speeds and reducing power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments are illustrated by way of example, and not bylimitation, in the figures of the accompanying drawings, whereinelements having the same reference numeral designations represent likeelements throughout. It is emphasized that, in accordance with standardpractice in the industry various features may not be drawn to scale andare used for illustration purposes only. In fact, the dimensions of thevarious features in the drawings may be arbitrarily increased or reducedfor clarity of discussion.

FIG. 1 is a diagram of a memory array, in accordance with one or moreexample embodiments;

FIG. 2 is a diagram of the memory array configured to illustrate bitline sharing for a MUX 2 (Bit-interleave-2) structure, in accordancewith one or more example embodiments;

FIG. 3 is a diagram of a memory array configured to illustrate aboundary example of a YMUX 2 application of a shared bit line structure,in accordance with one or more example embodiments;

FIG. 4 is a diagram of a memory array configured to illustrate bit linesharing for a YDEC design for MUX 4 application, which has a sharedRead-Pass-Gate, in accordance with one or more example embodiments;

FIG. 5 is a diagram of a memory array configured to illustrate bit linesharing for a YDEC design for MUX 2 application, which has a sharedRead-Pass-Gate, in accordance with one or more example embodiments;

FIG. 6 is a close-up view of a portion of the memory array illustratedin FIG. 4, in accordance with one or more example embodiments;

FIG. 7 is a diagram illustrating Write-Pass-Gates associated with amemory array having N=2 memory columns, which has a sharedWrite-Pass-Gate, in accordance with one or more example embodiments;

FIG. 8 is an isometric view of a memory array, in accordance with one ormore example embodiments; and

FIG. 9 is a flowchart of a process for forming a memory array, inaccordance with one or more example embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are examples and are not intended to belimiting.

Device manufacturers are continually challenged to reduce the size ofvarious integrated circuits and semiconductor devices such as, forexample, memory arrays despite the overarching demand to increaseprocessing speeds while reducing power consumption of such devices.

Some memory arrays include a two-dimensional structure in which aplurality of neighboring memory columns individually include bit lineand bit line bar pairs in communication with one or more word lines thatspan the plurality of memory columns. In other words, there are twotimes the number of bit lines and bit line bars as there are memorycolumns in a two-dimensional memory array that have one or more wordlines spanning a plurality of memory columns.

Some two-dimensional structures also include a spacing compliant withparticular design rules, e.g., Design Rule Check (“DRC”) spacing,between the plurality of memory columns to ensure that the memorycolumns work properly. Such spacing increases the overall peripheral orlayout size of a memory array as more and more memory columns areincluded. The spacing between memory columns in these two-dimensionalstructures also reduces speed capabilities of a particular memory arraybecause of, for example, the distance between the memory columns.

Bit lines are often associated with bit line switches that facilitate abit line to be any of Read-selected/Write-selected/Not-selected. Thereare often two times the number of bit line switches as there are memorycolumns in two-dimensional memory arrays. Such bit line switchesincrease power consumption and reduce processing speeds. Additionally,the inclusion of peripheral circuits such as bit line switches, numerousword lines that span the plurality of memory columns, numerous localinput/output (“LIO”) pre-charge P-type metal-oxide semiconductor(“PMOS”) circuits, LIO Y-pass-gate (read/write) metal-oxidesemiconductor (“MOS”) circuits, and the like result in a peripheral areaof a memory array that is greater than a minimum possible peripheralarea that might otherwise be achievable but for the presence of suchperipheral circuitry.

For example, some two-dimensional memory arrays include a number of LIOPre-charge-PMOS and Read/Write-pass-gate circuits associated with eachbit line and bit line bar pair that spans across the two-dimensionalmemory array equal to two times the number of memory columns included inthe two-dimensional memory array. Similarly, there are two times thenumber of LIO Y-pass-gate (Read/Write-pass-gate) MOS circuits as thereare LIO's.

Two-dimensional memory arrays are not readily adaptable to share ormerge a bit line and a neighboring bit line bar to eliminate the spacingbetween memory columns. The spacing cannot be eliminated because theneighboring memory columns will conflict with one another when a wordline is activated. The parasitic coupling capacitance between two activebit-lines creates undesirable signal noise, reduces processing speedcapabilities and increases power consumption.

FIG. 1 is a diagram of a memory array 100 according to one or moreexample embodiments. The memory array 100 has a shared bit linestructure for a MUX N (Bit-interleave N) application. In someembodiments, the memory array 100 is configured to provide a memorycircuit that occupies a minimal amount of spacing, whether such spacingis in a peripheral sense (e.g. two-dimensional occupied space) oroverall three-dimensional spacing. In some embodiments, the memory array100 also increases processing speeds and reduces power consumption whencompared to some two-dimensional memory arrays.

The memory array 100 includes N memory columns 101 a-101 n (hereinaftercollectively referred to as memory column(s) 101 where appropriate).

The memory array 100 also includes a series of bit lines (“BL”) 105a-105 n (hereinafter collectively referred to as BL 105 whereappropriate) and bit line bars (“BLB”) 107 a-107 n (hereinaftercollectively referred to as BLB 107 where appropriate). In someembodiments, the sequence of BL's and BLB's as illustrated are readilyswapped to change the order of BL's with respect to BLB's whilemaintaining the alternating sequence of BL's to BLB's. Accordingly, whenreferring generally to a “bit line” such reference refers to either a BLor a BLB depending on the embodiment. As such, in some embodiments, thememory array 100 includes N+1 bit lines.

The memory array 100 additionally includes N word lines (“WL”) 109 a-109n (hereinafter collectively referred to as WL 109 where appropriate).The memory array 100 further includes local input/outputs (“LIO”) 111a-111 n (hereinafter collectively referred to as LIO 111 whereappropriate).

Memory column 101 a is associated with BL 105 a, bit line bar (“BLB”)BLB 107 a, WL 109 a, and LIO 111 a. Memory column 101 b is associatedwith the BLB 107 a, BL 105 b, WL 109 b, and LIO 111 b. Memory column 101n is associated with BLB 107 n, BL 105 n, WL 109 n, and LIO 111 n. Thememory array 100, in other words, includes any quantity of memorycolumns 101, bit lines 105, bit lines bars 107, word lines 109 and LIO's111 such that the population of memory columns 101=N, bit lines105/107=N+1, and word lines 109=N. The number of LIO's 111 included inthe memory array 100 is any quantity of LIO's 111. In some embodiments,the memory array 100 includes N LIO's 111, N+1 LIO's 111, etc.

In some embodiments, the memory column 101 a and memory column 101 b areadjacent. Memory column 101 a and memory column 101 b share BLB 107 a,for example, based on a switching between a logic pass [0] and a logicpass [1]. Sharing BLB 107 a between logic passes [0/1] makes it possibleto eliminate spacing between the memory column 101 a and memory column101 b, thereby reducing the size of the memory array 100 toward aminimum overall size and increasing processing speeds when compared tosome two-dimensional memory arrays having significant spacing.Additionally, sharing BLB 107 a between memory column 101 a and memorycolumn 101 b makes it possible to reduce the quantity of “bit lineswitches,” or LIO per-charge PMOS circuits, included in a memory array,such as memory array 100, thereby conserving space. Because there arefewer bit line switches in the memory array, in some embodiments, powerconsumption is reduced compared to some two-dimensional memory arraystructures having more bit line switches.

In some embodiments, WL's 109 are configured to be formed such that theWL's 109 are substantially orthogonal to the BL's 105 and BLB's 107. Forexample, in some embodiments, BL's 105 and BLB's 107 are in a sameplane. WL's 109, accordingly, are substantially orthogonal to the planethat includes the BL's 105 and the BLB's 107. In some embodiments, WL's109 are part of a continuous inter-leaved WL 109 that winds throughmemory columns 101 in a manner that facilitates sharing bit lines suchas portions of the continuous inter-leaved WL 109 being substantiallyorthogonal to the BL's 105 and BLB's 107.

In some embodiments, the memory columns 101 are associated with WL's 109to facilitate sharing neighboring BL's 105 and/or BLB's 107.Bit-interleaving such as the discussed sharing of BL's 105 and/or BLB's107 paired with having WL's 109 that are associated with memory columns101 in the manner described eliminates the coupling effect discussedabove. In some embodiments, the bit line sharing makes it possible toreduce power consumption and/or increase processing speed capabilitiesof the memory array 100.

In some embodiments, the memory array 100, BL's 105, BLB's 107, WL's109, and LIO's 111 comprise one or more conductive materials implantedor otherwise formed as one or more layers in or on a semiconductorsubstrate so that the conductive materials or layers are routed for thecorresponding line or LIO, for example. In other embodiments, the memoryarray 100, BL's 105, BLB's 107, WL's 109, and LIO' s 111 compriseindividual modules assembled on one or more semiconductor substrates.

For ease of understanding, some of the figures include an XYZ axis togenerally illustrate the directional relationships described regardingone or more example embodiments.

FIG. 2 is a diagram of the memory array 200 configured to illustrate ashared BL for a MUX 2 N (Bit-interleave-2) structure, according to oneor more example embodiments. In some embodiments, a shared BL is alsoapplicable when joining separate memory arrays such as multiple memoryarrays 100, discussed above. In this example, the memory array 200 isconfigured to have two memory arrays 100 that each have two memorycolumns 101 (i.e., N=2). As such, the memory array 200 includes a firstmemory array 100 a similar to memory array 100 discussed above and asecond memory array 100 b also similar to memory array 100 discussedabove.

Memory array 200 is configured such that memory array 100 a and memoryarray 100 b share BL 105 b/a that is illustrated to be the end BL formemory array 100 a and the end BL for memory array 100 b.

FIG. 3 is a diagram of a memory array 300 configured to illustrate aboundary example of a YMUX 2 application of a shared bit line structure,such as those discussed above, according to an example embodiment. Inthis example, the memory array 300 is configured similarly to memoryarray 200 discussed above to have two memory arrays 100 that have twomemory columns 101. Accordingly, memory array 300, like memory array200, is an example of a combination of two N=2 memory column structures.The BL's 105 and BLB's 107 are associated with BL switches 301 a-301 j(hereinafter collectively referred to as BL switch 301 whereappropriate) within memory arrays 100 a and 100 b.

Memory array 300 is in communication with data line (“DL”) 303 a, DL 303b, data line bar (“DLB”) 305 a and DLB 305 b. DL 303 a and DLB 305 a areassociated with a sense amplifier (“SA”) 307 a. DL 303 b and DLB 305 bare associated with a SA 307 b. BL switch 301 a is null. BL switch 301 bis in communication with DL 303 a, BL switch 301 c is in communicationwith DLB 305 a, BL switch 301 d is in communication with DLB 305 a, BLswitch 301 e is in communication with DL 303 a, BL switch 301 f is incommunication with DL 303 b, BL switch 301 g is in communication withDLB 305 b, BL switch 301 h is in communication with DLB 305 b, BL switch301 i is in communication with DL 303 b and BL switch 301 j is incommunication with another DL [not shown]. BL switch 301 j, for example,is associated with another memory column or memory array (not shown) orpart of a BL switch pair at the boundary of memory array 300.

In this example embodiment, BL switch 301 a is null and BL switch 301 jis in communication with another DL. As such, each of the memory arrays100 a and 100 b have 2*N BL switches 301 (i.e., memory array 100 a hasfour BL switches 301 and memory array 100 b has four BL switches 301).The memory array 300, therefore, includes eight BL switches 301 incommunication with two SA's 307.

Such arrangement, as discussed above, results in a space occupied by thememory array 300 to be driven toward a minimum, power consumption to bedriven toward a minimum and processing speed capabilities of the memoryarray 300 to be driven toward a maximum while still accommodating aminimal amount circuitry to achieve the example embodiment. In additionto reduced space occupancy, power consumption and increased processingspeeds, the reduction in features compared to some two-dimensionalmemory array structures also reduces the overall complexity of thememory array 300 thereby improving reliability and/or manufacturabilityas well.

According to this example embodiment, memory array 300 is also incommunication with Y-directional decoder output (“YDEC”) signals 311a-311 j (hereinafter collectively referred to as YDEC signal 311). YDECsignals 311 are associated with one of a logic pass [0] and a logic pass[1]. The number of YDEC signals 311 for logic pass [0] is N YDEC signals311. The number of YDEC signals 311 for logic pass [1] is N YDEC signals311. In total, there is an equivalent number of YDEC signals 311 to thenumber of BL switches 301, or 2*N YDEC signals 311. In some embodiments,the total gate loading of all YDEC-signals is 2N*(Number of SA/IO).

FIG. 4 is a diagram of a memory array 400 configured to illustrate thediscussed bit line sharing for a YDEC design for MUX 4, according to anexample embodiment. In this example, the memory array 400 is configuredsimilarly to memory array 100 for an N=4 memory column structure.Accordingly, memory array 400 has N=4 memory columns 101 and N=4 WL's109. The BL's 105 and BLB's 107 are associated with BL switches 301a-301 g totaling N+1 bit lines.

Memory array 400 is in communication with DL 303, DLB 305. DL 303 andDLB 305 are associated with a SA 307. BL switch 301 a is null. BL switch301 b is in communication with DL 303, BL switch 301 c is incommunication with DLB 305, BL switch 301 d is in communication with DL303, BL switch 301 e is in communication with DLB 305, BL switch 301 fis in communication with DL 303, and BL switch 301 g is in communicationanother DL [not shown]. BL switch 301 g, for example, is associated withanother memory column or memory array [not shown], or is formed as partof a BL switch pair at the boundary of the memory array 400.

In this example embodiment, BL switch 301 a is null and BL switch 301 gis in communication with another DL. As such, the memory array 400 hasN+1 BL switches 301. The memory array 400, therefore, includes five BLswitches 301 in communication with one SA 307.

Memory array 400 has a column pitch 409 (i.e. a spacing between memorycolumn 101 a and memory column 101 c that is equal to the width ofmemory column 101 b between them). In other words, there is noadditional metal spacing regulated by DRC between neighboring memorycolumns 101. Such arrangement, as discussed above, results in a spaceoccupied by the memory array 400 to be driven toward a minimum, whileincreasing processing speed capabilities of the memory array 400 towarda maximum. Further, because certain BL's 105 and BLB's 107 areconfigured to share some of the BL switches 301, BL switch 301 orpre-charge power consumption is reduced toward a minimum powerconsumption. Such accomplishments are done while still accommodating aminimal amount circuitry to achieve the example embodiment.

According to this example embodiment, memory array 400 is also incommunication with YDEC signals 311 a-311 g. There is an equivalentnumber of YDEC signals 311 to the number of BL switches 301. In otherwords, there are N+1 YDEC signals 311 and N+1 switches per LIO in amux-N design (i.e. five YDEC signals 311 b-311 f for a MUX-4 design).The YDEC signals 311 are increased to be N+1, (i.e., logic passes [0],[0]+[1], [1]+[2], [2]+[3], and [3]) but actually are reduced in overallwire loading (N+1)*(number of SA/IO) compared to the memory array 300discussed above and compared to some two-dimensional memory arrays.Accordingly, the overall reduction in YDEC signals 311 compared tomemory array 300 and to some two-dimensional memory arrays not onlyreduces space occupied by the memory array 400, reduces power consumedby the memory array 400 and increases processing speed capabilities ofthe memory array 400, but also reduces the number of features includedin the memory array 400 toward a minimum, thereby reducing the overallcomplexity of the memory array 400 and improving reliability andmanufacturability as well.

FIG. 5 is a diagram of a memory array 500 configured to illustrate thediscussed bit line sharing for a YDEC design for MUX 2, according to anexample embodiment. In this example, the memory array 400 is configuredsimilarly to memory array 100 for an N=4 memory column structure.Accordingly, memory array 400 has four memory columns 101. The memoryarray 500 is similar to the memory array 400, discussed above, but isconfigured to accommodate two SA's 307 like memory array 300 discussedabove with respect to FIG. 3. BL's 105 and BLB's 107 are associated withBL switches 301 a-301 h to accommodate the communication with SA 307 aand SA 307 b.

Memory array 500 is in communication with DL 303 a, DL 303 b, DLB 305 aand DLB 305 b. DL 303 a and DLB 305 a are associated with SA 307 a. DL303 b and DLB 305 b are associated with a SA 307 b. BL switch 301 a isnull. BL switch 301 b is in communication with DL 303 a, BL switch 301 cis in communication with DLB 305 a, BL switch 301 d is in communicationwith DL 303 a, BL switch 301 e is in communication with DL 303 b, BLswitch 301 f is in communication with DLB 305 a, BL switch 301 g is incommunication with DL 303 a, BL switch 301 h is in communication with DL303 b.

In this MUX 2 example embodiment, BL switch 301 a is null and BL switch311 h is in communication with DL[2] 303 (not shown). Accordingly, toaccommodate SA 307 a and SA 307 b with a minimal number of BL switches,the memory array 500 includes 2+1 BL switches 301 or N+1 BL switches 301per LIO (per SA 307).

The memory array 500 has a column pitch 409 (i.e., a spacing betweenmemory column 101 a and memory column 101 c that is equal to the widthof memory column 101 b between them). In other words, there is noadditional metal spacing regulated by DRC between neighboring memorycolumns 101. Such an arrangement, as discussed above, results in a spaceoccupied by the memory array 500 to be driven toward a minimum andprocessing speed capabilities of the memory array 500 to be driventoward a maximum while still accommodating a minimal circuitry toachieve the example embodiment.

According to this example embodiment, memory array 500 is also incommunication with YDEC signals. The number of YDEC-signals is 2+1(i.e., [0], [0]+[1], and [1]). The total gate-loading ofYDEC-signal=(2+1)*(number of SA/IO), or N=2. Accordingly, the overallreduction in YDEC signals 311 compared to memory array 300, and to sometwo-dimensional memory array, not only reduces space occupied by thememory array 500, reduces power consumed by the memory array 500 andincreases processing speed capabilities of the memory array 500, butalso reduces the number of features included in the memory array 500toward a minimum, thereby reducing the overall complexity of the memoryarray 500 and improving reliability and manufacturability as well.

FIG. 6 is a close-up view of a portion of memory array 400, discussedabove. The illustrated portion of memory array 400 demonstrates a sharedBL pre-charge and YDEC_READ, according to an example embodiment.

A BL pre-charge line, in this example, has three BL pre-charge nodes,601 a, 601 b and 601 c (hereinafter collectively referred to as BLpre-charge node 601 where appropriate). The BL pre-charge nodes 601 areconfigured to receive a signal from a processor or controller such asmemory controller 805, discussed below, to provide pre-charge power tothe memory array 400. In this example, there are three BL pre-chargenodes 601, or in other words N+1 BL pre-charge nodes 601. In thisexample, BLB 107 a is shared between memory column 101 a and memorycolumn 101 b, and BL pre-charge node 601 b is shared between memorycolumns 101 a and 101 b, for example. Similarly, with BL 105 b is one ofshared with a next memory column 101, such as memory column 101 cdiscussed above, or not shared with any next memory column 101 if BL 105b is at the boundary of a memory array, for example. BL pre-charge node601 c, accordingly, depending on embodiment, is shared to pre-charge BL105 b, for example.

This sharing of pre-charge nodes 601 reduces power consumption by thememory array 400 during pre-charge of the BL's 105 and BLB's 107, aswell as space consumed by the memory array 400 compared to atwo-dimensional memory array that includes BL-pre-charge nodes having anequal quantity to the quantity of BL's and BLB's included in thetwo-dimensional memory array.

YDEC's 311 a, 311 b and 311 c are associated with BL 105 a, BLB 107 aand BL 105 b. In this example, there are three YDEC's 311, or in otherwords N+1 YDEC's 311. With BLB 107 a being shared between memory column101 a and memory column 101 b, YDEC 311 b is also shared. Similarly,with BL 105 b being shared in memory array 400, YDEC 311 c is alsoshared. In some embodiments, such as those in which a memory array doesnot have a next memory column 101, the YDEC 311 c, or any other YDEC atthe boundary of such a memory column, is not shared.

This sharing of YDEC's 311 reduces power consumption, increasesprocessing speed capabilities, reduces space occupied by the memoryarray 400 and reduces the complexity of the memory array 400 compared toa two-dimensional memory array that includes YDEC's populated to aquantity equal to a quantity of BL's and BLB's included in thetwo-dimensional memory array.

FIG. 7 is a diagram illustrating Write-Pass-Gates associated with amemory array as discussed above having N=2 memory columns, according toan example embodiment. For a memory array having N=2 memory columns 101,such as those discussed above, the number of write-pass-gates in such acircuit would be three, or in other words N+1. Compared to atwo-dimensional memory array that includes 2*N write-pass-gates per LIO111, the memory arrays discussed above make it possible to configure thememory array to include write-pass-gate 701 a, write-pass-gate 701 b andwrite-pass-gate 701 c (hereinafter collectively referred to aswrite-pass-gate 701 where appropriate) for a memory array having 2=Nmemory columns 101. In some embodiments, however, any quantity ofwrite-pass-gates 701 are included in the memory array.

Such a reduction in quantity of write-pass-gates 701 from that of atwo-dimensional memory array reduces the complexity of, reduces powerconsumption by, and reduces space occupied by, a memory array whileincreasing processing speed potential of the memory array when comparedto a two-dimensional memory array such as that discussed above.

FIG. 8 is an isometric view of memory array such as memory array 100discussed above, according to an example embodiment. The memory array100 includes a 3D-array 801, a LIO 803, a controller 805 and a word linedriver (“WL-driver”) 807. In this example, the 3D-array 801 is in directcommunication with the LIO 803 and the WL-driver 807. In otherembodiments, the 3D-array is in communication with the LIO 803 and/orthe WL-driver 807 indirectly by way of an intermediary component of thememory array. The 3D-array 801 is in communication with the controller805 by way of the LIO 803 and/or the WL-driver 807. In otherembodiments, the 3D-array 801 is in direct communication with thecontroller 805. The LIO 803 and the WL-driver 807 are in directcommunication with the controller 805. In other embodiments, like the3D-array, the LIO 803 and/or the WL-driver 807 are in communication withthe controller 805 indirectly by way of at least one intermediarycomponent of the memory array.

The 3D-array 801 is configured to include one or more memory columns101, discussed above. BL 105 is illustrated as running between the LIO803 and the 3D-array 801. WL 109 is illustrated as running between theWL-driver 807 and the 3D-array 801 in a direction orthogonal to that ofthe BL 105. YDEC 311 and XDEC 809 are illustrated as running between thecontroller 805 and the WL-driver 807. YMUX 811 and ZMUX 813 areillustrated as running between the LIO 803 and the controller 805.

The LIO 803, in some embodiments, is a single LIO that is configured tofacilitate communications to the 3D-array 801 as a whole. In otherembodiments, the LIO 803 includes any number of LIO's 803 configured tobe in communication with one or more of the memory columns 101 includedin the 3D-array 101. For example, in other embodiments, LIO 803 includesa number of LIO's 803 equal to the number of memory columns 101 in the3D array. In other embodiments, LIO 803 includes lesser number of LIO'sthan the number of memory columns included in 3D-array 803. In yetanother embodiment, LIO 803 includes a greater number of LIO's than thenumber of memory columns 101 included in the 3D-array 801.

FIG. 9 is a flowchart of a process 900 for forming a memory arrayaccording to one or more example embodiments. The process begins withoperation O901 in which a first memory column is formed, the firstmemory column including a first bit line, a first word line, and asecond bit line. In some embodiments, the first word line issubstantially orthogonal to the first word line and the second wordline.

Then, in operation O903, a second memory column is formed, the secondmemory column including the second bit line, a second word line, and athird bit line. In some embodiments, the second word line issubstantially orthogonal to the second bit line and the third bit line.According to various embodiments, the first memory column and the secondmemory column are configured to be a three-dimensional array. In otherembodiments, the first memory column, the second memory column and athird memory column are formed to have a column pitch between the firstmemory column and the third memory column that is equal to the width ofthe second memory column.

Next, in operation O905, the second bit line is shared between the firstmemory column and the second memory column.

The process continues to operation O907 in which one or more memoryarray components are shared between the first memory column and thesecond memory column. The memory array components comprise, for example,any of a bit line switch, a BL pre-charge node, or a YDEC, or othersuitable component.

Then, in operation O909, a word line driver is provided such that theword line driver is in direct communication with the one or more of thefirst word line, the second word line, and a three-dimensional arraythat includes one or more of the first word line and the second wordline.

Next, in operation O911, a local input/output is provided in directcommunication with one or more of the first bit line, first word line,the second bit line, the second word line, and a three-dimensional arraythat includes one or more of the first bit line, the first word line,the second bit line and the second word line.

One aspect of this description relates to a memory array that includes afirst column of memory cells, a second column of memory cells and a setof switching elements. The first column of memory cells includes a firstbit line, a first word line and a second bit line. The second column ofmemory cells includes the second bit line, a second word line and athird bit line. The first and the second column of memory cells areconfigured to share the second bit line. The first and second bit lineare in a first plane. At least a portion of the first word line and atleast a portion of the second word line are in a second planeintersecting the first plane. An amount of bit line switching elementsin the set of bit line switching elements is equal to N*2, where N is anamount of columns of memory cells in the memory array.

Another aspect of this description relates to a memory array thatincludes a first conductive layer, a first column of memory cells and asecond column of memory cells. The first conductive layer comprises afirst bit line; a second bit line; and a third bit line. The firstcolumn of memory cells comprises the first bit line; the second bitline; and a first word line. The second column of memory cells comprisesthe second bit line; the third bit line; and a second word line. Thefirst column of memory cells and the second column of memory cells areconfigured to share the second bit line. At least two of the first bitline, the second bit line or the third bit line are in a first plane.The first word line and the second word line are in a second plane, thesecond plane intersecting the first plane.

Still another aspect of this description relates to a method for forminga memory array, the method including forming a first column of memorycells, forming a second column of memory cells, and sharing the secondbit line between the first column of memory cells and the second columnof memory cells. The first column of memory cells comprises a first bitline; a first word line; and a second bit line, the first bit line andthe second bit line being in a first plane. The second column of memorycells comprises the second bit line; a second word line, and a third bitline. The first word line and the second word line are in a second planeintersecting the first plane.

It will be readily seen by one of ordinary skill in the art that thedisclosed embodiments fulfill one or more of the advantages set forthabove. After reading the foregoing specification, one of ordinary skillwill be able to affect various changes, substitutions of equivalents andvarious other embodiments as broadly disclosed herein. It is thereforeintended that the protection granted hereon be limited only by thedefinition contained in the appended claims and equivalents thereof.

What is claimed is:
 1. A memory array comprising: a first column ofmemory cells comprising: a first bit line; a first word line; and asecond bit line; a second column of memory cells comprising: the secondbit line; a second word line; and a third bit line; and a set ofswitching elements, wherein the first column of memory cells and thesecond column of memory cells are configured to share the second bitline; the first bit line and the second bit line are in a first plane;at least a portion of the first word line and at least a portion of thesecond word line are in a second plane intersecting the first plane; andan amount of switching elements in the set of switching elements isequal to N*2, where N is an amount of columns of memory cells in thememory array.
 2. The memory array of claim 1, wherein the second planeis substantially orthogonal to the first plane.
 3. The memory array ofclaim 1, wherein a switching element of the set of switching elementscomprises a pass-gate transistor having a first terminal configured toreceive a control signal.
 4. The memory array of claim 1, furthercomprising: a set of data lines; and a sense amplifier coupled to theset of switching elements by the set of data lines.
 5. The memory arrayof claim 4, wherein the set of switching elements comprises: a firstswitching element coupled to the first bit line; a second switchingelement coupled to the second bit line; a third switching elementcoupled to the second bit line; and a fourth switching element coupledto the third bit line.
 6. The memory array of claim 5, wherein the setof data lines comprises: a first data line coupled between a firstterminal of the sense amplifier and a first terminal of the firstswitching element; a second data line coupled between a second terminalof the sense amplifier and a first terminal of the second switchingelement; a third data line coupled between the second terminal of thesense amplifier and a first terminal of the third switching element; anda fourth data line coupled between the first terminal of the senseamplifier and a first terminal of the fourth switching element.
 7. Thememory array of claim 1, further comprising: a first memory arraycomprising: the first column of memory cells; and the second column ofmemory cells; a second memory array comprising: a third column of memorycells comprising: the third bit line; a third word line; and a fourthbit line; and a fourth column of memory cells comprising: the fourth bitline; a fourth word line; and a fifth bit line, wherein the first memoryarray and the second memory array are configured to share the third bitline; and the third column of memory cells and the fourth column ofmemory cells are configured to share the fourth bit line.
 8. The memoryarray of claim 7, wherein the fourth bit line and the fifth bit line arein the first plane; and at least a portion of the third word line and atleast a portion of the fourth word line are in the second plane.
 9. Amemory array comprising: a first conductive layer comprising: a firstbit line; a second bit line; and a third bit line; a first column ofmemory cells comprising: the first bit line; the second bit line; and afirst word line; and a second column of memory cells comprising: thesecond bit line; the third bit line; and a second word line, wherein thefirst column of memory cells and the second column of memory cells areconfigured to share the second bit line; at least two of the first bitline, the second bit line or the third bit line are in a first plane;and the first word line and the second word line are in a second plane,the second plane intersecting the first plane.
 10. The memory array ofclaim 9, wherein the second plane is substantially orthogonal to thefirst plane.
 11. The memory array of claim 9, wherein the first wordline comprises a first conductive material extending in a firstdirection; the first bit line comprises a second conductive materialextending in a second direction different from the first direction; andthe second bit line comprises a third conductive material extending inthe second direction.
 12. The memory array of claim 11, wherein thesecond word line comprises a fourth conductive material extending in thefirst direction; and the third bit line comprises a fifth conductivematerial extending in the second direction.
 13. The memory array ofclaim 9, further comprising: a set of pre-charge circuits coupled to theat least two of the first bit line, the second bit line or the third bitline; a set of switching elements coupled to at least the first bitline, the second bit line or the third bit line; a set of data lines;and a sense amplifier coupled to the set of switching elements by theset of data lines.
 14. The memory array of claim 9, wherein the firstconductive layer further comprises: a fourth bit line comprising a firstconductive material extending in a first direction; and a fifth bit linecomprising a second conductive material extending in the firstdirection.
 15. The memory array of claim 14, further comprising: a firstmemory array comprising: the first column of memory cells; and thesecond column of memory cells; and a second memory array comprising: athird column of memory cells comprising: the third bit line; a fourthbit line; and a third word line; and a fourth column of memory cellscomprising: the fourth bit line; a fifth bit line; and a fourth wordline, wherein the first memory array and the second memory array areconfigured to share the third bit line; the third column of memory cellsand the fourth column of memory cells are configured to share the fourthbit line; the fourth bit line and the fifth bit line are in the firstplane; and the third word line is in the second plane.
 16. A methodcomprising: forming a first column of memory cells comprising: a firstbit line; a first word line; and a second bit line, the first bit lineand the second bit line being in a first plane; forming a second columnof memory cells comprising: the second bit line; a second word line, thefirst word line and the second word line being in a second planeintersecting the first plane; and a third bit line; and sharing thesecond bit line between the first column of memory cells and the secondcolumn of memory cells.
 17. The method of claim 16, further comprisingcausing the first plane to be substantially orthogonal to the secondplane.
 18. The method of claim 16, further comprising sharing a set ofmemory array elements between the first column of memory cells and thesecond column of memory cells.
 19. The method of claim 18, wherein theset of memory array elements comprises: a set of bit line switchingelements; and a set of bit line pre-charging circuits.
 20. The method ofclaim 19, wherein the set of memory array elements further comprises: aset of data lines; and a set of sense amplifiers.